Furnace



llan. 11, 1938. J, MORTENS-ON 2,105,004

FURNACE Original Filed Aug. 16, 1933 2 Sheets-Sheet l 5"@ i@ Joa-N MoRTNsoN ff j? T NvLN-ro -ro musa/f3 Jan. 11, 19.38. MORTENSON 2,105,004

FURNACE Y Original Filed Aug. 16, 1933 2 Sheets-Sheet 2 .Z0-f'- @cu-1N MoRTENsoN INx/.LNTQQ M/@MW .A T TOR NLJS Patented Jan. 11, 1938 UNITED STATES PATENT OFFICE Application August 16,

1933, Serial N0. 685,345

Renewed June 9, 1937 6 Claims.

My invention relates to furnaces, and more particularly to furnaces of the muilie type, and the principal object of this invention is to provide a new and improved apparatus of this character.

In the drawings accompanying the specification and forming a part of this application I have shown, for purposes of illustration, various forms which my invention may assume, and in these drawings:

Figure 1 is a vertical sectional View showing an illustrative embodiment of my invention,

VFigure 2 is a vertical sectional view corresponding to the line 2 2 of Figure 1 and drawn to a slightly enlarged scale,

Figure 3 is a vertical sectional view corresponding to the line 3--3 of Figure 1 and drawn to a slightly enlarged scale,

Figure 4 is an enlarged fragmentary sectional view, partly disassembled, showing the construction of the combustion iiues, while Figure 5 is a fragmentary view, similar to Figure 2 but showing a diiferent embodiment of my invention.

In the embodiment of my invention shown in Figures 1 through 4, there is provided a furnace I Il of refractory material, such as fire brick or the like, having side walls II, end walls I2 and I3, and an arched dome, I4. The furnace I0 is provided at its lower part with inwardly extending portions I5, forming longitudinally extending shoulders I5, and supported upon the shoulders I6 is the open bottom of an inverted U- shaped muiiie I'I, the defining wall of which is spaced from the furnace walls and dome to form therewith a conducting chamber I8 closed at the ends, but otherwise entirely enveloping theY exterior of the muie wall. The wall I2 is provided with an opening I9 through which material to be treated can be admitted to the furnace, and the opening I9 is normally closed by a door 20. TheV wall I3 is provided adjacent its lower end with openings ZI for the admission of the combustion flue assembly, hereinafter described, while the dome I4 is provided with an exhaust stack 22V communicating with the chamber I8 of the furnace IU. Y

The furnace I 0 is provided with a pair of elongated cylindrical combustion flues 23 and 24 extending Vbeneath the muiile I'I substantially from the wall I2 tothe wall I3 of the furnace. Although two of such lues are herein shown, a different number may be employed, depending upon the size of the furnace and the amount of heat required in the furnace.

The ues 23 and 24 are each formed of a number of sections 25, of refractory material, and of relatively thin cross-section, preferably cylindrical, and provided with tongue and groove joints 26 interengaging at their ends. Each section 25 is formed of two semi-cylindrical parts 2l, also provided along their meeting edges with tongue and groove joints 28 to prevent dislocation of the parts 27. The tongue and groove joints 26 and 28 cooperate to provide a combustion-tight flue when all of the sections are assembled.

The combustion ues 23 and 24 are supported by a plurality of blocks 30, each comprising upper and lower halves 29 and 31, each half being provided with a semi-circular aperture of a size to closely fit the assembled sections 25. The blocks 3D preferably embrace the ues at the juncture of the sections 25, this construction preventing the sagging of the flues and cooperating to maintain a combustion-tight chamber.

The combustion :dues 23 and 24 terminate adjacent the wall I3 of the furnace I0 and at this point cooperate with burner blocks 3l, adapted to support suitable burners (not shown) of any well known type and construction, which discharge into the combustion flues 23 and 24. The opposite ends of the flues 23 and 24 extend to a point short of the wall I2 to form therewith a space 32 which communicates with the chamber I8. A baille 33 extends between the Wall I2 and the ends of the flues 23 and 24 to prevent communication between the space 32 and the interior of the mule Il.

Disposed within the open bottom of the muille I'I, and supported by the upper halves 29 of the supporting blocks 3i) is a plurality of supporting members 34, commonly called pigs or skid rails, adapted to support transverse bars 35 which may be placed at suitable positions along the length of the furnace. 'I'he bars 35 are for the purpose of supporting trays containing articles to be treated in the furnace in the ordinary manner.

In operation, and with the articles suitably disposed within the furnace and the burners operating, the products of combustion discharged into the combustion ues adjacent the entrance thereto, follow the path shown by the arrows in Figure 1, and under inuence of the draft exerted by the exhaust stack 22 travel through the flues 23 and 24 which form combustion chambers, radiating heat through the relatively thin walls of the sections 25 directly into the open bottom of the muflie I'I; and the products of L combustion` continue to the space 32 an-d thence through the chamber I8 and around the exterior of the muie I1 finally finding exit through the stack 22.

It will be appreciated that because of the interior and exterior heating of the muille I1, a much lower temperature may be employed in the combustion chambers formed by the ues 23 and 2d, and the fiues are made much thinner than those ordinarily used, providing greater and more rapi-d heat radiation. And because of the comparatively low temperature within the combustion chambers 23 and 24, the walls and bottom of the furnace Hi can be lined with suitable insulating material (not shown) of any well known type, thereby permitting reductio-n in the cross-sectional thickness of the walls of the furnace as compared to the thicknesses usually considered necessary, reducing also the amount of expensive refractory material required, while at the same time greatly reducing the heat loss due to radiation from the exterior of the furnace. Furthermore, because of the particular manner of supporting the ilues 23 and 24, a greater surface is provide-d to radiate heat, and because the open end of the muiiie l1 directly overlies the ues 23 and 24, heat is radiated directly within the interior of the muflie, while the products of combustion are employed to directly heat the entire exterior of the muilie I1.

This construction greatly increases the eiiciency of the furnace and produces the two-fold function of speeding up the furnace operation and reducing the cost of operating the furnace.

In the embodiment of the invention shown in Figure 5, the upper halves 29 of the supporting blocks 30 are omitted, and only the lower halves 31 are used, the latter supporting the flues 23 and 24 in cradle-type manner, and the pigs or skid rails7 are elongated, as shown at 36, to support the bars 35 at the proper level. This construction reduces the number of parts comprising the furnace, as well as increases the radiating surface of the filles) 23 and 24.

Both embodiments of my invention disclose a flue construction which can be readily and easily assembled and disassembled, thereby providing a construction which can be replaced in part or in its entirety without necessitating lengthy shutdowns of the furnace.

It will be understood by those skilled in the art that the disclosure herein accomplishes at least the principal object of my invention, and it will further be understood that the` invention has uses and advantages other than those herein particularly referred to, and it will be apparent that various changes and modications may be made without departing from the spirit of the invention; accordingly it will be appreciated that the disclosure herein is illustrative only yand the invention not limited thereto.

I claim:

1. A furnace, comprising: an enclosing shell, the lower portion of which provides a compartment adapted for the reception of heating means, and the upper portion of which defines an article treating chamber unobstructedly oom- .municating with said heating means compartment; heating means disposed in said heating means compartment, and comprising a conduit for products of combustion, spaced from the bottom wall of said compartment, disposed below the limits of said article treating chamber, the wall of said conduit being disposed to radiate heat directly into said chamber, and to radiate heat onto the side and bottom walls of said compartment, whence said radiated heat is reected into said chamber; and means for supporting said conduit in position, and constructed and arranged to dene vertical flues opening into said article treating chamber.

2. A furnace, comprising: an enclosing shell, the lower portion of which provides a compartment adapted for the reception of heating means, and the upper portion of which defines an article treating chamber unobstructedly communicating with said heating means compartment; heating means disposed in said heating means compartment, andY comprising a conduit for products of combustion, spaced from the bottom wall of said compartmenhdisposed below the limits of said article treating chamber, the wall of said conduit being disposed to radiate heat directly into said chamber, and to radiate heat onto the side and bottom walls of said compartment, whence said radiated heat is reflected into said chamber; and means for supporting said conduit in position, and constructed and arranged to define vertical ues opening into said article treating chamber, said means being constructed of refractory material and providing radiating surfaces in addition to those of said conduit for radiating heat emanations into said treating chamber.

3. A furnace, comprising: an enclosing shell, the lower portion of which provides a compartment adapted for the reception of heating means, and the upper portion of which defines an article treating chamber unobstructedly communicating with said heating means compartment; heating means disposed in said heating means compartment, and comprising a conduit for products of combustion, spaced from the bottom wall of rsaid compartment, disposed below the limits of said article treating chamber, the wallv of said conduit being disposed to radiate heat directly into said chamber, and to radiate heat 1Q onto the side and bottom walls of said compartment, whence said radiated heat is reflected into said chamber; Yand means for supporting said conduit in position, and constructed and arranged to define vertical flues opening into said article treating chamber, said means being constructed of refractory material and providing radiating surfaces in addition to those of said conduit for radiating heat emanations into said treating chamber, said means extending to a point with respect to said treating chamber as to provide a supporting medium for articles treated in said treating chamber.

4. A furnace, comprising: an outer enclosing shell, the lower portion of which provides a compartment adapted for the reception of heating means; an inner shell enclosed by said outer shell and spaced therefrom to define a passage terminating above said compartment, said inner shell defining a chamber having its bottom substantially entirely open and unobstructed throughout its extent and forming substantially a continuation of the heating means compartment of said outer shell; and heating means disposed in said heating means compartment, restricted to a position below the open mouth of said chamber, and spaced above the bottom wall of said compartment, and comprising a conduit for products of combustion, the wall of said conduit being disposed to radiate heat directly into said chamber through the unobstructed bottom thereof, and to radiate heat onto the side and bottom walls of said compartment, whence said radiated heat is reected into said chamber, said conduit communicating with said passagefor heating the 75 outside of said inner shell directly by the products of combustion which are employed to heat said conduit.

5. A furnace, comprising: an enclosing shell, the lower portion of which provides a compartment adapted for the reception of heating means, and the upper portion of which defines an article treating chamber unobstructed from wall to wall, and communicating with said heating means compartment; and heating means disposed in said heating means compartment, comprising a plurality of conduits of refractory material supported in side by side spaced relation, spaced from the bottom Wall of said compartment, and spaced belov.T the limits of said article treating chamber, the walls of said conduitsbeing disposed toI radiate heat directly into said chamber, and to radiate heat onto the side and bottom walls of said compartment and toward each other, whence said radiated heat is reflected into said chamber, each of said conduits having combustion means discharging thereinto, and constructed and arranged to discharge the products of combustion through said conduits, and exteriorly of said article treating chamber and of said heating compartment, and from its inlet to its discharge outlet being removed from the interior of said article treating chamber.

6; A furnace, comprising: an enclosing shell, the lower portion of which provides a compartment adapted for the reception of heating means, and the upper portion of which defines an article treating chamber unobstructed from wall to wall, and communicating with said heating means compartment; and heating means dis'- posed in said heating means compartment, and comprising a plurality of conduits of refractory material for products of combustion, supported in side by side spaced relation, spaced from the bottom wall of said compartment, and spaced below the limits of said article treating chamber, the walls of said conduits being disposed to radiate heat directly into said chamber, and to radiate heat onto the side and bottom walls of said compartment and toward each other, whence said radiated heat is reected into said chamber, said conduits being constructed and arranged so that the internal cross-sectional area of each conduit is greater than the spaces between said conduits, and between said conduits and the side and bottom Walls of said compartment, each of said conduits having combustion means discharging thereinto, and constructed and arranged to discharge said products of combustion exteriorly of said article treating chamber and of said heating compartment, and from its inlet to its discharge outlet being removed from the interior of said article treating chamber.

JOHN MOR'IENSON. 

